On a site of program production such as a broadcast station, in case a program is produced, necessary video materials are prepared in advance and selected or edited in the subsequent editing work to provide a program of a predetermined duration. To prepare video materials, it is necessary to shoot a variety of images in many places such as studios and outdoor locations. For example, a 45-minute program may be produced from as many as over 200 photographed video materials. It is a key to efficient program production to retrieve desired images without delay from a huge quantity of photographed video materials, that is, to reduce the time required to retrieve video materials.
As a video material retrieval method, there is a typical technique in which a photography director or their assistant records memo information related to details of a video material such as the target of photography and the photography state in association with the photographed material during or after photography and performs retrieval based on the memo information in the editing process.
Photographed materials are recorded in association with memo information, so that a memo input person has had to add photographed material identification information to identify a particular photographed material the memo pertains to while inputting the memo. For example, in case a memo is inputted while a video material is being photographed, the memo input person has to display and check the identification information on the material being photographed for example on the monitor screen or the finder of a camera used for photographing and input the identification information on the material as a memo in order to add the identification information before inputting an original memo to be recorded. This requires a heavy workload related to memo input. An exemplary document preparation device capable of storing and managing inputted characters in units of predetermined character strings is disclosed in Patent Reference 1.    Patent Reference 1: JP-A-8-185452, pp. 3-8, FIG. 2